Re: [PATCH v4] hwmon: (pt5161l) Fix bugs in pt5161l_read_block_data()

[Guenter Roeck]

On Fri, Apr 10, 2026 at 12:25:55AM +0000, Pradhan, Sanman wrote:
> From: Sanman Pradhan <psanman@xxxxxxxxxxx>
> 
> Fix two bugs in pt5161l_read_block_data():
> 
> 1. Buffer overrun: The local buffer rbuf is declared as u8 rbuf[24],
>    but i2c_smbus_read_block_data() can return up to
>    I2C_SMBUS_BLOCK_MAX (32) bytes. The i2c-core copies the data into
>    the caller's buffer before the return value can be checked, so
>    the post-read length validation does not prevent a stack overrun
>    if a device returns more than 24 bytes. Resize the buffer to
>    I2C_SMBUS_BLOCK_MAX.
> 
> 2. Unexpected positive return on length mismatch: When all three
>    retries are exhausted because the device returns data with an
>    unexpected length, i2c_smbus_read_block_data() returns a positive
>    byte count. The function returns this directly, and callers treat
>    any non-negative return as success, processing stale or incomplete
>    buffer contents. Return -EIO when retries are exhausted with a
>    positive return value, preserving the negative error code on I2C
>    failure.
> 
> Fixes: 1b2ca93cd0592 ("hwmon: Add driver for Astera Labs PT5161L retimer")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Sanman Pradhan <psanman@xxxxxxxxxxx>

Applied.

Thanks,
Guenter